Designed by two ex-Shanghai policemen, and named after them, the Fairbairn-Sykes Fighting Knife was issued to many units during the Second World War, most notably the Special Operations Executive (SOE), the Special Air Service (SAS) and the Commandos. It is often referred to as 'the commando dagger'.

Experts in the martial arts, learned while on the job in Shanghai, the inventors also put together a booklet detailing many street-fighting techniques that could be used with weapons such as their knife, or indeed when unarmed. They also gave hand-to-hand combat training lessons.